5th gear star washer source

[3Phase]

The 'legs' have to be there on the starfish washer or its replacement.

The shift pawl pins do move between the 'legs' during the up/down shift indexing.

Some of the causes of the broken starfish washer:

Upshifting without the clutch or just fast upshifting.

The shift drum tries to slide out of the case to the left as it rotates and positions the shift forks during upshifts. The lateral movement's not bad during a "normal" upshift when the gears aren't under load. When they're loaded, the shift drum has to force the shift forks to move gears on the transmission abacus/Main Axle Assesmbly (Input Shaft)/Drive Axle (Output Shaft). If the whole shift drum assembly is in good shape and it just pushed out to far during one really 'hard' upshift, that's when you can replace the washer and it won't just break the next time you go riding. If the drum assembly's worn, it'll keep moving out of the case and the shift pawl will slice the legs off the starfish like a sushi chef.


What wears?

The left-hand shift drum bearing race wears and can't hold the shift drum.

The shift drum retaining dowel pin can be worn or bent.

Bent or worn shift forks, they make the shift drum work harder to shift gears.

The shift fork shaft/oil pump drive gear shaft can be bent. The oil pump gear retaining clip can be worn or taking a time out in the oil pan because it was installed backwards, bevel side out, on the shift fork shaft.

When the shift pawl wears out, it won't sit up straight on its seat when you shift and it snags the starfish washer, usually during the 4th-to-5th gear upshift. That can leave the bike stuck in 5th gear because if you're traveling, it might be a while before you think about downshifting and the 4th gear shift drum pin will eventually take a swan dive out of the drum and join that oil pump drive gear retaining clip for a swim in the oil pan.

[3Phase]

Let me understand, what you're saying is making a thicker washer for the SHIFT PAWL PIN to hit/stop against?

Yes that sounds good, the only problem I see which is easily checked, is if the shift pawl pins (circled in red on my photo) that hit the little shift drum pins have to hit them in a tangent direction, in other words at 90 degrees to the radius. (if that makes sense). If I understand correctly, a thick washer would be hit by the shift pawl pins in a straight line with the radius, which may cause problems.

No. The shift pawl pins and the shift pawl pin bosses should never, ever, hit the starfish washer or the shift drum pins during any shift, up or down.

The Stainless Steel washer I used is just a hardware store SS washer. It has some 'spring' to it like the original washer so it won't just bend like a regular washer and it'll hold the pins in their holes. That particular washer I used happens to be 0.051" thick, 0.012" thicker than the 0.039" OEM special washer but the point is that it's only eighty-five cents, not eleven dollars US or tuppence in UK real money.

I don't see why you couldn't make a better version of the A washer, only with more "feet" on it to do the same job as the two long pins, and grind down the longer pins.

The shift drum pins are all the same length. There is a reason that Yamaha drilled shallow holes for two of the pins but I've forgotten what it is. If you wanted, you could just weld or glue all of the pins in place and never, ever, worry about the special washer ever again but where's the fun in that?

My personal view is - what Yamaha made works well, the stops, how the shift pawl pins engage, the only problem I see is the star washer breaking, and the simple repair I and a few others have done works. Fix the part that's broke, not the bit that works. However, I also like modding so have a go and let us know how you get on.

That's why I replaced the special washer that is No Longer Available with an inexpensive washer that you can probably find along the side of the road while you're pushing your busted XS1100 that won't shift to the hardware store to buy a washer.